Percorrer por autor "Silva, Ana Isabel"
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- Astrocyte-derived TNF and glutamate critically modulate microglia activation by methamphetaminePublication . Canedo, Teresa; Portugal, Camila Cabral; Socodato, Renato; Almeida, Tiago Oliveira; Terceiro, Ana Filipa; Bravo, Joana; Silva, Ana Isabel; Magalhães, João Duarte; Guerra-Gomes, Sónia; Oliveira, João Filipe; Sousa, Nuno; Magalhães, Ana; Relvas, João Bettencourt; Summavielle, TeresaMethamphetamine (Meth) is a powerful illicit psychostimulant, widely used for recreational purposes. Besides disrupting the monoaminergic system and promoting oxidative brain damage, Meth also causes neuroinflammation, contributing to synaptic dysfunction and behavioral deficits. Aberrant activation of microglia, the largest myeloid cell population in the brain, is a common feature in neurological disorders triggered by neuroinflammation. In this study, we investigated the mechanisms underlying the aberrant activation of microglia elicited by Meth in the adult mouse brain. We found that binge Meth exposure caused microgliosis and disrupted risk assessment behavior (a feature that usually occurs in individuals who abuse Meth), both of which required astrocyte-to-microglia crosstalk. Mechanistically, Meth triggered a detrimental increase of glutamate exocytosis from astrocytes (in a process dependent on TNF production and calcium mobilization), promoting microglial expansion and reactivity. Ablating TNF production, or suppressing astrocytic calcium mobilization, prevented Meth-elicited microglia reactivity and re-established risk assessment behavior as tested by elevated plus maze (EPM). Overall, our data indicate that glial crosstalk is critical to relay alterations caused by acute Meth exposure.
- Blockingmethamphetamine-induced microglia reactivity by targeting glutamate receptorsPublication . Summavielle, Teresa; Canedo, Teresa; Silva, Ana Isabel; Andrade, Elva Bonifácio; Almeida, Tiago O.; Bravo, Joana; Terceiro, Ana Filipa; Canedo, Teresa; Silva, Ana Isabel; Magalhães, Ana; Relvas, João B.; Bonifácio Andrade, Elva; Bravo, JoanaExposure to psychostimulants has been classically associated with damage to neuronal terminals. However, it is now accepted that interaction between neuronal and glial cells also contributes to the addictive behavior. We have recently shown that acute methamphetamine (Meth), a powerful psychostimulant, causes microgliosis and increases microglia activation through astrocytic-TNF release1. We are now interested in clarifying the progression of neuroinflammation under chronic drug exposure and how different brain and immune cells contribute to this inflammatory process.To explore this, firstly, we performed a proteomic analysis, in different phases of the addictive process, in mice exposed to an escalating dosing of Meth for ten days (Meth10d). To validate the conditioning power of our model, mice were tested in a condition place preference (CPP) at 10d of Meth, and 2 or 10 days of withdrawal (WD). At all these time points, mice were seen to be strongly conditioned by Meth. Next, we conducted a proteomic analysis to compare the different time points (using the hippocampus, where we previously found robust microgliosis underMeth1). We found a proteome profile that varied substantially with exposure (Meth10d) and after a short- (WD2d)and long-term withdrawal (WD10d) periods. Interestingly, the most altered pathways were neuro transmitter-related.However, we also identified significant differences in Wnt signaling, which was previously linked to regulation of microglia reactivity. As such, we evaluated the microglia profile after chronic Meth exposure and at withdrawal. In the hippocampus, the number of microglia cells was significantly increased at Meth10d and remained also increased at WD2d. Microglia presented a more ameboid-like shape at Meth10d, but its ramified morphology was recovered at WD2d. Importantly, our proteomic data also revealed that during Meth withdrawal, several microglial receptors were down regulated, suggesting that microglia was in a “primed” state. In addition, as the crosstalk between neurons and microglia seems to be relevant for the behavioral expression of Meth, we are dissecting the modulation of microgliaby neurons under Meth exposure, to evaluate neuroimmune regulatory ligand-receptor pairs that seem to impact on the neuron-microglia interaction. Of note, some these ligand-receptor pairs seem to be down regulated by chronic Meth and during abstinence, which may be associated with reduced neuronal ability to down regulate microglia reactivity, and lead to increased neuronal damage. We fore see that these receptors may prove to be interesting therapeutic targets for the treatment of addiction, and therefore we will manipulate them to confirm their value in reducing relapse rates and improve addiction treatments.
- Deciphering the astrocytic and synaptic changes under chronic alcohol exposure using a self-administration paradigmPublication . Rodrigues, Ana Margarida; Canedo, Teresa; Terceiro, Ana Filipa; Tedim-Moreira, Joana; Silva, Ana Isabel; Magalhães, Ana; Relvas, João; Summavielle, TeresaDrug abuse is characterized by a compulsive and persistent drug-seeking behaviour, despite the harmful emotional, physical and social consequences. Our laboratory has previously found that the neuronal-glial crosstalk is critical in relaying the changes caused by acute exposure to psychoactive drugs through neuroimmune mechanisms. We have also reported that microglia can engulf postsynaptic components in the prefrontal cortex (PFC) of mice after repeated alcohol exposure and this led to increased anxiety in mice. The adverse effects of alcohol on the central nervous system (CNS) are well described, with astrocytes becoming reactive and displaying changes in gene expression, activity and proliferation. However, the mechanisms involved are not yet fully understood. We are currently characterizing the astrocytic response under chronic alcohol consumption, taking into account the crucial interaction between neuronal and glial cells in the development and maintenance of addiction. Using a well-established voluntary alcohol drinking paradigm, we are evaluating alcohol-associated changes in PFC astrocytes, synapses and their behavioural correlates. Our preliminary results indicate similar alcohol consumption patterns between males and females, however, males, but not females, present altered weight gain and experience a significant increase in inhibitory synapse density after chronic exposure to ethanol when compared to the control group. Our work is contributing to a better understanding of the impact of chronic alcohol intake and may lead to the development of new strategies for pharmacological intervention in drug addiction, based on the targets identified as critical for the neuronal-glial crosstalk.
- IL-10 and Cdc42 as critical modulators in methamphtamine-induced neuroinflammationPublication . Silva, Ana Isabel; Socodato, Renato; Pinto, Carolina; Terceiro, Ana Filipa; Canedo, Teresa; Relvas, João Bettencourt; Saraiva, Margarida; Summavielle, Teresa; Summavielle, TeresaPsychoactive substances, such as Methamphetamine (Meth), can induce complex neuroinflammatory responses that modulate the neuron-glia cross talk and strongly affect behavioral responses. Recently we have reported that Meth stimulates astrocytes to release tumor necrosis factor (TNF) and glutamate, leading to microglial activation, microgliosis and loss of risk-assessment. Here, we started by investigating the anti-inflammatory power the cytokine interleukin-10 (IL-10), resorting to astrocyte and microglia primary transfected with different FRET probes and exposed to Meth (100µM), to elucidate the mechanisms involved. Then after, we confirmed these results in vivo, by employing a transgenic mouse model that overexpresses IL-10 (pMT-10), in time-controlled manner, and administering a binge Meth dosing (4 x 5mg/kg, with 2h intervals). In vitro, our findings reveal that the presence of recombinant IL-10 (rIL-10) counteracts Meth-induced excessive glutamate release in astrocytes, which significantly reduced microglial activation. This reduction was associated with the modulation of astrocytic intracellular calcium (Ca2+) dynamics, particularly by restricting the release of Ca2+ from the endoplasmic reticulum to the cytoplasm. Furthermore, we identify the small Rho GTPase Cdc42 as a crucial intermediary in the astrocyte-to-microglia communication pathway under Meth. In vivo, we observed that IL-10 overexpressing prevented Meth-induced neuroinflammation, microgliosis and Meth-induced behavioral changes. These findings enhance our understanding of Meth-related neuroinflammatory mechanisms, suggesting IL-10 and Cdc42 as putative therapeutic targets, and strengthen the view of a neuroimmune nature for addiction.
- IL-10 and Cdc42 modulate astrocyte-mediated microglia activation in methamphetamine-induced neuroinflammationPublication . Silva, Ana Isabel; Socodato, Renato; Pinto, Carolina; Terceiro, Ana Filipa; Canedo, Teresa; Relvas, João Bettencourt; Saraiva, Margarida; Summavielle, TeresaMethamphetamine (Meth) use is known to induce complex neuroinflammatory responses, particularly involving astrocytes and microglia. Building upon our previous research, which demonstrated that Meth stimulates astrocytes to release tumor necrosis factor (TNF) and glutamate, leading to microglial activation, this study investigates the role of the anti-inflammatory cytokine interleukin-10 (IL-10) in this process. Our findings reveal that the presence of recombinant IL-10 (rIL-10) counteracts Meth-induced excessive glutamate release in astrocyte cultures, which significantly reduces microglial activation. This reduction is associated with the modulation of astrocytic intracellular calcium (Ca2+) dynamics, particularly by restricting the release of Ca2+ from the endoplasmic reticulum to the cytoplasm. Furthermore, we identify the small Rho GTPase Cdc42 as a crucial intermediary in the astrocyte-to-microglia communication pathway under Meth exposure. By employing a transgenic mouse model that overexpresses IL-10 (pMT-10), we also demonstrate in vivo that IL-10 prevents Meth-induced neuroinflammation. These findings not only enhance our understanding of Meth-related neuroinflammatory mechanisms, but also suggest IL-10 and Cdc42 as putative therapeutic targets for treating Meth-induced neuroinflammation.
- Methamphetamine activates rac1 in striatal microgliaPublication . Terceiro, Ana Filipa; Canedo, Teresa; Silva, Ana Isabel; Magalhães, Ana; Relvas, João; Summavielle, Teresa; Summavielle, TeresaMethamphetamine (Meth), a powerful psychostimulant, induces profound synaptic and morphological alterations alongside with detrimental neuroinflammatory responses, in the brain reward system. Yet, the mechanisms regulating these processes in microglial cells are not clear. We have previously shown that exposing WT mice to Meth (4x5mg/kg, 2h intervals) induces microgliosis concomitant with decreased microglia cell volume and ramification. Furthermore, psychostimulants are known to induce structural plasticity mechanisms in neurons, and Rho GTPases, important regulators of the actin cytoskeleton, are involved in these responses. Here, we evaluate if Rho GTPases, specifically rhoA, rac1 and cdc42, are critical in the response to Meth in microglia. Exposing WT mice to the samepattern of Meth administration, we found an increase in the activation of rac1 in the striatum, 15 min following the last administration of Meth. To further explore these results, we then used a conditional mice model for ablation of rac1 in adult microglia (Rac1fl/fl:Cx3cr1CreER+) and exposed these mutants to the same pattern of Meth administration. We found that rac1 ablation is sufficient to prevent Meth-induced morphological alterations in the striatum. Currently, we are assessing whether ablation of rac1 is also sufficient to prevent the neuroinflammatory response induced by Meth. Overall, we identified rac1 as a novel target of Meth in microglial cells. With these results, we expect to clarifyif targeting Rho GTPases may contribute to improving the treatment of addictive disorders.
- Motivation as a lever for service excellencePublication . Silva, Ana Isabel; Oliveira, Mónica; Silva, SusanaIn recent years, we have seen a change in mentalities in the way organisations are managed. Day by day, we realize that an organization's human resources are the key to success. In this sense, human resources management assumes an essential position that will allow to achieve levels of motivation and satisfaction of employees central to the performance of the organization. In the hotel sector, we still observe organizations with little focus on human resources management. However, it is from the sectors where this management becomes vital. The satisfaction and motivation of employees are directly reflected in customer satisfaction, compromising the future of the hotel unit. This work aims to understand the impact of the employee's motivation on their performance, according to their perspective. Thus, the method used was the questionnaire survey, addressed to all employees of the InterContinental Porto — Palácio das Cardosas hotel. Data analysis was performed through descriptive and statistical analysis, with resources to the SPSS (Statistical Package for Social Sciences) program. The results obtained did not allow us to observe any direct relationship between employee motivation and performance, according to their perspective.
- Peripheral metabolism in rat with olanzapine subchronic treatment supplemented with acetyl-L carnitinePublication . Amorim, Manuela; Silva, Ana Isabel; Alves, Cecília Juliana; Monteiro, Pedro R.; Magalhães, Ana; Summavielle, TeresaOlanzapine (Olz) have been reported to promote higher risk for metabolic side-effects, such as obesity, dyslipidemia, and diabetes. Moreover/On the other hand, acetyl-L-carnitine (ALC) has been reported to improve homeostasis. This study aims to explore if ALC could improve metabolic homeostasis due to Olz effects on a rodent model. We investigated the effects of subchronic administration of Olz and with the addition of ALC on body weight gain and glucose metabolism in Wistar rats. Mid-term Olz exposure in rats significantly increases blood glucose levels in fasting and after the overload of glucose compared to the sali-ne-treated group (p<0.05). However, in rats mid-term treated with olanzapine plus acetyl-L-carnitine had no significant differences in fasting blood glucose levels compared to the saline-treated group. The findings suggest that ALC added to Olz treatment appeared to be effective to improve glucose metabolism during olanzapine subchronic treatment.
- Repeated exposure to ketamine in adolescent rats results in persistent anxiety in the adulthoodPublication . Amorim, Manuela; Bravo, Joana; Silva, Ana Isabel; Alves, Cecília Juliana; Monteiro, Pedro; Magalhãess, Ana; Summavielle, TeresaAdolescent development of the prefrontal cortex (PFC) is accompanied by important changes in glutamatergic, GABAergic and dopaminergic circuitries, susceptible to modulation by N-methyl-D-aspartate receptors (NMDAR) antagonists. Repeated ketamine was associated with social and memory deficits, but other relevant factors, such as anxiety, were not sufficiently addressed. The present study aimed to examine the behavioral and molecular consequences of repeated exposure to ketamine with a particular focus in anxiety. Methods. We treated male adolescent Wistar rats, starting postnatal day (PND) 35, with ketamine (30 mg/kg, i.p, 7 days). Behavioral evaluation was conducted in the adulthood (PND 60). The elevated plus maze (EPM) and open field tests were used to evaluate anxiety and locomotion, while sociability and novelty recognition were assessed through the novel object recognition (NOR) and the sociability and social novelty tests. At the end of the behavioral evaluation, brains were dissected and the prefrontal cortex used for biochemical evaluation. Results. Analysis of the elevated plus maze (EPM) data revealed a ketamine-induced anxiety-like profile, corroborated by the open field data. Ketaminetreated rats also failed to increase contact time with a conspecific in the social affiliation test and with an unknown rat in the novelty preference test. At the molecular level, frontal expression levels of tyrosine hydroxylase were found decreased. Conclusion. Altogether, these results show that repeated ketamine-exposure in the adolescent may result in long-term anxiety
- The role of RAC1 in methamphtamine-induced neuroinflammationPublication . Terceiro, Ana Filipa; Canedo, Teresa; Silva, Ana Isabel; Magalhães, Ana; Relvas, João; Summavielle, Teresa; Summavielle, TeresaMethamphetamine (Meth), a powerful psychostimulant, induces detrimental neuroinflammatory responses, in the brain reward system that seem to contribute to maintenance of addictive behaviour. Yet, the mechanisms regulating these processes in microglial cells are not clear. We have previously shown that exposing WT mice to Meth (4x5 mg/kg, 2h intervals) induces microgliosis concomitant with decreased microglia cell volume and ramification. Furthermore, psychostimulants are known to induce structural plasticity mechanisms in neurons, and Rho GTPases, important regulators of the actin cytoskeleton, are involved in these responses. Here, we assessed Rho GTPases, specifically rhoA, rac1 and cdc42, activation in response to Meth in microglia. Exposing WT mice to the same pattern of Meth administration, we found an increase in the activation of rac1 in the striatum, 15 min following the last administration of Meth. To further explore these results, we then used a conditional mice model for ablation of rac1 in adult microglia (Rac1fl/fl:Cx3cr1CreER+) and exposed these mice to the same pattern of Meth administration. Rac1 ablation was sufficient to prevent Meth-induced morphological alterations in the striatum. Currently, we are assessing the role of rac1 in the behavioural response to Meth, using a locomotor sensitization test. Overall, we identified rac1 as a novel target of Meth in microglial cells. With these results, we expect to clarify if targeting Rho GTPases may contribute to improving the treatment of addictive disorders.